Not open source. I find Yandex to be objectively the most superior search engine for all purposes, as they work outside Western jurisdictions. Better privacy than Google/Bing.
If you want a "private" search engine, Searx metasearch with "default language (all)" option works about 85% as good as Yandex.
Edit: 85% is only meant for text/link results. Yandex also has reverse image search, video search and other things with no competition in sight.
If you want lesser private but more ordinary results, Startpage is great.
Everything else is same tier or bad/useless. DDG (western censorship), Ecosia, Qwant, Google, BingGPT and others included.